Local Air Quality Studies

Toronto has four air quality monitoring stations across the city that measure air pollution levels every hour, yet very little is known about air pollution and the related health risks at the local community level. That is why the City of Toronto’s Environment & Energy Division, in collaboration with Toronto Public Health, have initiated an ambitious project to do Local Air Quality Studies.

These studies rely on air pollution data from a range of sources including transportation, energy use, and industrial releases. Thanks to the City’s ChemTRAC program, the studies can access a much more localized source of chemical release data that includes small businesses. The study also considers air pollution that migrates into Toronto from other regions such as Southern Ontario and the United States.

Local air quality study locations

Findings to date

While only two Local Air Quality Studies have been completed so far, these studies have already identified serious cumulative health risks including respiratory illness and cancer as a result of air pollution in Toronto’s communities. Eight cancer-causing chemicals have been identified at levels of concern in local airsheds and five substances exceed the Provincial government's air quality limits.

8 Carcinogens of Concern

5 Chemicals Exceed Air Quality Limits

1,3-Butadiene

1,4-Dichlorobenzene

Acetaldehyde

Benzene

Benzo[a]pyrene

Chromium (VI)

Formaldehyde

Tetrachloroethylene

Benzene

Benzo[a]pyrene

Nitrogen Oxides

Particulate Matter 10

Particulate Matter 2.5

The largest source of pollution is coming from vehicles travelling along the city’s highways, which is also the main reason for elevated cancer risks to residents living nearby.